Petroleomics by Traveling Wave Ion Mobility–Mass Spectrometry Using CO₂ as a Drift Gas

Abstract

The technique of choice for petroleomics has been ultra-high-resolution and high-accuracy Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), but other techniques such as ion mobility have been shown to provide additional or alternative information about crude oil composition. Using the traveling wave ion mobility (TWIM) cell of a hybrid Q-TWIM-TOF first-generation Synapt instrument and electrospray ionization in both the positive and negative ion modes, different crude oil samples with different polar compound profiles and petro fuels (diesel and gasoline) with or without additives were analyzed using either CO₂ or N₂ as the drift gas. Parameters such as gas pressure, velocity, and wave height were optimized for each type of crude oil or fuel sample. The ability of TWIM–MS to separate crude oil components according to their classes was verified by comparison with FT-ICR data. Results showed separation of several classes of polar compounds (NO, O₂, and N), and their separation was improved using CO₂, which also enhanced the resolution between adjacent <i>m</i>/<i>z</i> species. Additives and contaminants presented in petro fuels could also be easily separated and characterized